I am using G4hLowEnergyIonisation with a combination of G4hSRIM2000p. I usually change energy reagion for G4hSRIM200p using G4hLowEnergyIonisation::SetHighEnergyForProtonParametrisation() method. However, it does not work after version 7.0. As a new feature after version 7.0, the G4hParamterisedLossModel gives a high energy limit for each parameterisations, i.e SRIM2000 is 100MeV, and the energy value is used as a upper limit of energy range. This is always used in G4hLowEnergyIonisation::InitializeParameteriation() at G4hLowEnergyIonisation::BuildPhysicsTable(). Therefore even if user change the "protonHighEnergy", it is reset at InitalizeParameterisation().
Yes, protonHighEnergy was defined by the model upper energy limit. It seems not to be optimal. Now it is fixed and this value will be min(user defined value, model upper limit)